Polyphenylene ether resins are known in the art and exhibit a desirable combination of chemical, physical and electrical properties over a temperature range of more than about 650.degree. F., extending from a brittle point of about -275.degree. F. to a heat distortion temperature of about 375.degree. F. This combination of properties renders polyphenylene ether resins suitable for a broad range of applications. However, the usefulness of polyphenylene ether resins is limited in some applications as a consequence of processability, impact resistance, and chemical resistance.
As a result, polyphenylene ether resins have been blended with other polymer resins in order to improve processability, impact resistance and chemical resistance. For example, the Cizek U.S. Pat. No. 3,383,435 discloses blends of polyphenylene ether and one or more styrene resins having improved properties. The Deets et al U.S. Pat. No. 4,578,423 discloses blends of polyphenylene oxide with styrene-acrylonitrile (SAN) or acrylonitrile- butadiene-styrene (ABS) polymers. These blends are disclosed as exhibiting improved solvent resistance without loss in heat distortion temperature and impact strength. Similar blends of polyphenylene oxide with SAN or ABS polymers are also disclosed in the Trementozzi U.S. Pat. No. 4,360,618.
It is further known to include additional polymers in polyphenylene ether-styrene polymer blends in order to further improve the overall physical and chemical properties of the blend compositions. For example, the Lee, Jr. U.S. Pat. No. 3,835,200 discloses blends of polyphenylene ether, a graft copolymer of a diene rubber with a styrene monomer, and a normally rigid block copolymer of a vinyl aromatic compound and a conjugated diene. These blends are disclosed as exhibiting improved toughness. The Deets et al U.S. Pat. No. 4,405,753 discloses blends of polyphenylene oxide, a SAN or ABS polymer, and a styrene-maleic anhydride copolymer, which blends are disclosed as exhibiting advantageous impact strength and heat distortion temperatures. The Hambrecht et al U.S. Pat. No. 4,526,927 discloses blends including a polyphenylene ether, a styrene polymer, and, as a component for improving the impact strength, a block copolymer obtained by reacting an ethylene copolymer with an active polymeric anion. Hartsing, Jr. et al disclose in U.S. Pat. No. 4,588,623 a blend of a poly(arylether) polymer, a styrene and/or acrylic copolymer, and a compatibilizing amount of a polyhydroxy ether. Additional blend compositions including polyphenylene ether, a polystyrene polymer, and one or more additional polymers are disclosed in the Ueno et al U.S. Pat. No. 4,309,513, the Abe et al U.S. Pat. No. 4,460,743 and the Sugio et al U.S. Pat. No. 4,556,685.
Thus, various blends of polyphenylene ether and styrene polymers are known which exhibit one or more improved physical and/or chemical properties.